1. Field of the Invention
The present invention relates to an image blur correction apparatus and a camera that correct an image blur caused by shaking by changing the position of an image pickup device.
2. Description of the Related Art
Conventionally, in a camera equipped with an image blur correction apparatus that corrects an image blur caused by camera shake due to hand shaking or the like by changing the position of an image pickup device, for example, a voice coil motor (hereunder, referred to as “VCM”) is applied as an actuator that changes the position of the image pickup device. Japanese Patent Application Laid-Open Publication No. 2008-225135 discloses an image blur correction apparatus that moves an image pickup device by means of a VCM. Further, for example, as disclosed in Japanese Patent Application Laid-Open Publication No. 2008-299286, a VCM is also used for auto-focus driving of a lens.
To reduce the size of a camera body and improve the image blur correction performance, it is necessary to decrease the size of a driving mechanism of a VCM while maintaining the driving output thereof. To achieve this, for example, use of a permanent magnet with a strong magnetic force may be considered. However, if only the magnetic force of the permanent magnet is strengthened, the leakage of magnetic flux from the VCM will increase and in some cases the leakage may affect the operation of other electronic components contained in the camera.
Therefore, in order to prevent leakage of magnetic flux from a VCM in, for example, an image blur correction apparatus as disclosed in Japanese Patent Application Laid-Open Publication No. 2008-225135, for example, a method can be considered in which a magnetic body that covers the outer side of a permanent magnet is formed with a thick thickness.